U.S. patent number 10,136,657 [Application Number 15/750,065] was granted by the patent office on 2018-11-27 for freezer device for containers.
This patent grant is currently assigned to DAIKIN INDUSTRIES, LTD.. The grantee listed for this patent is DAIKIN INDUSTRIES, LTD.. Invention is credited to Noritaka Kamei, Kazuhide Mizutani.
United States Patent |
10,136,657 |
Kamei , et al. |
November 27, 2018 |
Freezer device for containers
Abstract
Disclosed is a container refrigeration apparatus including a
unit case of an inside air control system disposed outside a
container, the unit case housing an air pump therein. The container
refrigeration apparatus is provided with an air inlet unit
independent of the unit case. The air inlet unit and the air pump
are connected together by a tube. The air inlet unit is provided
with a membrane filter, and is disposed above the unit case.
Malfunctions of electrical components and corrosion on metallic
components due to moisture permeation into the unit case are
reduced.
Inventors: |
Kamei; Noritaka (Osaka,
JP), Mizutani; Kazuhide (Osaka, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
DAIKIN INDUSTRIES, LTD. |
Osaka-shi, Osaka |
N/A |
JP |
|
|
Assignee: |
DAIKIN INDUSTRIES, LTD.
(Osaka-Shi, JP)
|
Family
ID: |
57756103 |
Appl.
No.: |
15/750,065 |
Filed: |
August 22, 2016 |
PCT
Filed: |
August 22, 2016 |
PCT No.: |
PCT/JP2016/003801 |
371(c)(1),(2),(4) Date: |
February 02, 2018 |
PCT
Pub. No.: |
WO2017/038038 |
PCT
Pub. Date: |
March 09, 2017 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
|
US 20180213808 A1 |
Aug 2, 2018 |
|
Foreign Application Priority Data
|
|
|
|
|
Aug 28, 2015 [JP] |
|
|
2015-168743 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01D
69/02 (20130101); A23B 7/04 (20130101); F25D
23/00 (20130101); F25D 11/00 (20130101); F25D
17/042 (20130101); A23B 7/148 (20130101); F25D
11/003 (20130101) |
Current International
Class: |
A23B
7/148 (20060101); A23B 7/04 (20060101); F25D
11/00 (20060101); F25D 23/00 (20060101); B01D
69/02 (20060101); F25D 17/04 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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61-10143 |
|
Apr 1986 |
|
JP |
|
8-167 |
|
Jan 1996 |
|
JP |
|
9-105577 |
|
Apr 1997 |
|
JP |
|
2002-274608 |
|
Sep 2002 |
|
JP |
|
2006-52913 |
|
Feb 2006 |
|
JP |
|
2007-509309 |
|
Apr 2007 |
|
JP |
|
2012-136287 |
|
Jul 2012 |
|
JP |
|
2015-72103 |
|
Apr 2015 |
|
JP |
|
2016-61466 |
|
Apr 2016 |
|
JP |
|
WO 2015/049840 |
|
Apr 2015 |
|
WO |
|
Primary Examiner: Duke; Emmanuel
Attorney, Agent or Firm: Birch Stewart Kolasch & Birch,
LLP
Claims
The invention claimed is:
1. A container refrigeration apparatus which includes an inside air
control system configured to supply an interior of a container with
a mixed gas, wherein an inlet taking air into an air pump provided
to an interior of a unit case of the inside air control system is
formed in an air inlet unit independent of the unit case, the air
pump and the air inlet unit being connected together by an air
tube, and the air inlet unit is provided with an air-permeable,
waterproof membrane filter, and is disposed above the unit case of
the inside air control system.
2. The container refrigeration apparatus of claim 1, wherein the
unit case of the inside air control system is disposed in a space
below a condenser of an external storage space, and the air inlet
unit provided with the membrane filter is disposed in a space above
the condenser.
3. The container refrigeration apparatus of claim 2, wherein the
space, provided with the air inlet unit, above the condenser is a
blowout side space to which the air that has passed through the
condenser is blown.
4. The container refrigeration apparatus of claim 3, wherein the
air inlet unit includes an air box to which the membrane filter is
attached, and a filter cover which covers the membrane filter from
above.
5. The container refrigeration apparatus of claim 4, wherein the
air box of the air inlet unit is disposed on a side of an
electrical component box disposed in the space above the condenser.
Description
TECHNICAL FIELD
The present invention relates to a container refrigeration
apparatus including an inside air control system which controls a
composition of the air in the container.
BACKGROUND ART
Container refrigeration apparatuses that have been known in the art
include a refrigerant circuit performing a refrigeration cycle to
cool the air in a container for use, e.g., in marine transportation
(see, e.g., Patent Document 1). The container is loaded, for
example, with plants such as bananas and avocados. Plants perform
respiration by absorbing oxygen in the air and releasing carbon
dioxide even after they are harvested. As the plants respire, the
plants lose the nourishment and moisture stored in them, resulting
in a decrease in freshness of the plants. Thus, the oxygen
concentration in the container is preferably lowered not to cause
breathing problems.
Patent Document 1 discloses an inside air control system which,
using an adsorbent adsorbing a nitrogen component in the air
through pressurization, generates nitrogen-enriched air having a
higher nitrogen concentration and a lower oxygen concentration than
the air does, and supplies the nitrogen-enriched air to the
interior of the container, thereby reducing the oxygen
concentration of the air in the container to reduce the breathing
of the plants and easily keep the plants fresh. This inside air
control system sends, using an air pump, the pressurized air to an
adsorption column housing the adsorbent therein to perform an
adsorption operation in which a nitrogen component is adsorbed to
the adsorbent. Then, the inside air control system sucks the air
from the adsorption column using the air pump to perform a
desorption operation in which the nitrogen component that has been
adsorbed to the adsorbent is desorbed. As a result, the
nitrogen-enriched air is generated.
This inside air control system may be formed as one unit by housing
the components of the inside air control system in a hermetically
sealed unit case, and this unit may be attached to an exterior
space of the container refrigeration apparatus. Thus, even an
existing container, if the unit is retrofitted thereto, can control
the oxygen concentration in the interior of the container using the
nitrogen mixed gas.
CITATION LIST
Patent Document
[Patent Document 1] Japanese Unexamined Patent Publication No.
2015-072103
SUMMARY OF THE INVENTION
Technical Problem
If the unit case is airtight, a pressure inside the unit case may
be changed due to the temperature difference between the interior
and exterior of the unit case, and moisture may permeate through a
fine gap of the unit case into the unit case due to capillarity,
resulting in an unwanted situation where insulation failure occurs
in the electrical components. Thus, the unit case has to be an
air-permeable unit case. However, if the unit case is
air-permeable, ventilators may be splashed with sea water in the
marine atmosphere, and corrosion may occur on the electrical
components and metallic components in the unit case.
In view of the foregoing background, the present invention is
directed to a container refrigeration apparatus where a unit case
housing an inside air control system is disposed outside a
container. It is an object of the present invention to provide a
technique for reducing malfunctions of electrical components and
corrosion on metallic components due to moisture permeation into
the unit case.
Solution to the Problem
A first aspect of the present disclosure is directed to a container
refrigeration apparatus which includes an inside air control system
(60) configured to supply the interior of a container with a mixed
gas.
In the container refrigeration apparatus, an inlet taking air into
an air pump (31) provided to an interior of a unit case (36) of
housing the inside air control system (60) is formed in an air
inlet unit (75) independent of the unit case (36), the air pump
(31) and the air inlet unit (75) being connected together by an air
tube (85), and the air inlet unit (75) is provided with an
air-permeable, waterproof membrane filter (76), and is disposed
above the unit case (36) of the inside air control system (60).
According to the first aspect, the air inlet unit (75) provided
with the membrane filter (76) is disposed above the unit case (36)
of the inside air control system (60). Thus, the air inlet unit
(75) is less likely to be splashed with sea water even in the
marine atmosphere.
A second aspect of the present disclosure is an embodiment of the
first aspect of the present disclosure. In the second aspect, the
unit case (36) of the inside air control system (60) is disposed in
a space below a condenser (22) of an external storage space (S1),
and the air inlet unit (75) provided with the membrane filter (76)
is disposed in a space above the condenser (22).
According to the second aspect, the air inlet unit (75) is disposed
in the space above the condenser (22). Thus, the air inlet unit
(75) is much less likely to be splashed with sea water.
A third aspect of the present disclosure is an embodiment of the
second aspect of the present disclosure. In the third aspect, the
space, provided with the air inlet unit (75), above the condenser
(22) is a blowout side space to which the air that has passed
through the condenser (22) is blown.
According to the third aspect, the space above the condenser (22)
is the blowout side space to which the air that has passed through
the condenser (22) is blown, and is the space to which hot air is
blown. Thus, even if the air inlet unit (75) is splashed with sea
water, the water is likely to be evaporated.
A fourth aspect of the present disclosure is an embodiment of the
third aspect of the present disclosure. In the fourth aspect, the
air inlet unit (75) includes an air box (78) to which the membrane
filter (76) is attached, and a filter cover (79) which covers the
membrane filter (76) from above.
According to the fourth aspect, the filter cover (79) is provided
to cover the membrane filter (76). Thus, the air inlet unit (75) is
much less likely to be soiled with dirt and dust.
A fifth aspect of the present disclosure is an embodiment of the
fourth aspect of the present disclosure. In the fourth aspect, the
air box (78) of the air inlet unit (75) is disposed on a side of an
electrical component box (17) disposed in the space above the
condenser (22).
Advantages of the Invention
According to the first aspect, the air inlet unit (75) provided
with the membrane filter (76) thereon is disposed above the unit
case (36) of the inside air control system (60). Thus, the air
inlet unit (75) is less likely to be splashed with sea water even
in the marine atmosphere. This hardly allows water to permeate from
the air inlet unit (75) into the unit case (36) of the inside air
control system (60). Therefore, this can reduce malfunctions of
electrical components and corrosion on metallic components due to
moisture permeation into the unit case (36).
According to the second aspect, the air inlet unit (75) is disposed
in the space above the condenser (22). Thus, the air inlet unit
(75) is much less likely to be splashed with sea water. Therefore,
this can more reliably reduce malfunctions of electrical components
and corrosion on metallic components due to moisture permeation
into the unit case (36).
According to the third aspect, the space above the condenser (22)
is the blowout side space to which the air that has passed through
the condenser (22) is blown, and is the space to which hot air is
blown. Thus, even if the air inlet unit (75) is splashed with sea
water, the water is likely to be evaporated, thereby allowing water
to hardly permeate into the unit case (36) of the inside air
control system (60). This can more reliably reduce malfunctions of
electrical components in the unit case (36) and corrosion on
metallic components in the unit case (36).
According to the fourth aspect, the filter cover (79) is provided
to cover the membrane filter (76). Thus, the air inlet unit (75) is
much less likely to be splashed with sea water, thereby making it
possible to more reliably reduce malfunctions of electrical
components in the unit case (36) and corrosion on metallic
components in the unit case (36). The air inlet unit (75) is also
much less likely to be soiled with dirt and dust, thereby making it
possible to reliably reduce the filter clogged with dirt.
According to the fifth aspect, the air box (78) of the air inlet
unit (75) can be disposed by effectively utilizing the space on the
side of the electrical component box (17) disposed above the
condenser (22).
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view illustrating a container refrigeration
apparatus according to an embodiment of the present invention as
viewed from outside.
FIG. 2 is a side-face cross-sectional view illustrating a general
configuration of the container refrigeration apparatus.
FIG. 3 is a piping diagram illustrating a configuration of a
refrigerant circuit in the container refrigeration apparatus.
FIG. 4 is a piping diagram illustrating a configuration of a
controlled atmosphere system (CA system) in the container
refrigeration apparatus, together with the flow of air during a
first operation.
FIG. 5 is a piping diagram illustrating a configuration of the CA
system in the container refrigeration apparatus, together with the
flow of air during a second operation.
FIG. 6 is an enlarged perspective view illustrating main parts of
the container refrigeration apparatus.
FIG. 7 is a perspective view of an air inlet unit, when viewed from
the front-right side.
FIG. 8 is a perspective view of the air inlet unit, when viewed
from the rear-right side.
FIG. 9 is a perspective view of the air inlet unit, when viewed
from the rear-left side.
FIG. 10 is a perspective view of the air inlet unit, when viewed
from the front-left side.
FIG. 11 is a right side view of the air inlet unit.
FIG. 12 is a perspective view of the air inlet unit, when viewed
from the bottom.
DESCRIPTION OF EMBODIMENTS
Embodiments of the present invention will now be described in
detail with reference to the drawings. Note that the following
description of embodiments is merely examples in nature, and is not
intended to limit the scope, application, or uses of the present
invention.
As shown in FIGS. 1 and 2, a container refrigeration apparatus (10)
is provided to a container (11) for use in, e.g., marine
transportation, and cools the air in the container (11).
Boxed plants (15) are stored in the container (11). The plants (15)
breathes by absorbing oxygen (O.sub.2) in the air and releasing
carbon dioxide (CO.sub.2) into the air, and examples of such plants
(15) include fruit like bananas and avocados, vegetables, cereals,
bulbous plants, and natural flowers.
The container (11) has the shape of an elongate box with an open
end surface. The container refrigeration apparatus (10) includes a
casing (12), a refrigerant circuit (20), and a controlled
atmosphere (CA) system (inside air control system) (60), and is
attached to close an open end of the container (11).
<Casing>
As shown in FIG. 2, the casing (12) includes an exterior wall (12a)
disposed outside the container (11), and an interior wall (12b)
disposed inside the container (11). The exterior and interior walls
(12a, 12b) are made of aluminum alloy, for example.
The exterior wall (12a) is attached to the periphery of the opening
of the container (11) so as to close the open end of the container
(11). The exterior wall (12a) is formed such that the lower part of
the exterior wall (12a) protrudes into the container (11).
The interior wall (12b) is disposed to face the exterior wall
(12a). The interior wall (12b) protrudes into the container (11)
just like the lower part of the exterior wall (12a). A thermal
insulator (12c) fills the space between the interior and exterior
walls (12b, 12a).
As can be seen, the lower part of the casing (12) is formed so as
to protrude into the container (11). Thus, an external storage
space (S1) is formed outside the container (11) and in the lower
part of the casing (12), and an internal storage space (S2) is
formed inside the container (11) and in the upper part of the
casing (12).
As shown in FIG. 1, the casing (12) includes two access openings
(14) for maintenance arranged side by side in a width direction of
the casing (12). The two access openings (14) are closed
respectively by first and second access doors (16A, 16B) which are
openable and closable. Each of the first and second access doors
(16A, 16B) includes, just like the casing (12), an exterior wall,
an interior wall, and a thermal insulator.
As shown in FIG. 2, a partition plate (18) is disposed in the
interior of the container (11). This partition plate (18) is formed
in the shape of a substantially rectangular plate member, and
stands upright so as to face the wall of the casing (12) inside the
container (11). This partition plate (18) separates the internal
storage space (S2) from the interior of the container (11).
A suction opening (18a) is formed between the upper end of the
partition plate (18) and a ceiling surface of the container (11).
Air in the container (11) is taken into the internal storage space
(S2) through the suction opening (18a).
The internal storage space (S2) is further provided with a
partition wall (13) extending in the horizontal direction. The
partition wall (13) is attached to an upper end portion of the
partition plate (18), and has an opening in which internal fans
(26), which will be described later, are disposed. This partition
wall (13) partitions the internal storage space (S2) into a primary
space (S21) on the suction side of the internal fans (26), and a
secondary space (S22) on the blowout side of the internal fans
(26). In this embodiment, the partition wall (13) partitions the
internal storage space (S2) vertically such that the primary space
(S21) on the suction side is disposed above the secondary space
(S22) on the blowout side.
A floorboard (19) is disposed in the container (11) with a gap left
between the floorboard (19) and the bottom surface of the container
(11). Boxed plants (15) are placed on the floorboard (19). An
underfloor path (19a) is formed between the floorboard (19) and the
bottom surface of the container (11). A gap is left between the
lower end of the partition plate (18) and the bottom surface of the
container (11), and communicates with the underfloor path
(19a).
A blowout opening (18b) through which the air which has been cooled
by the container refrigeration apparatus (10) is blown into the
container (11) is provided at an end of the floorboard (19)
opposite from the open end of the container (11) (on the right side
in FIG. 2).
<Configuration of Refrigerant Circuit and Other
Components>
As shown in FIG. 3, the refrigerant circuit (20) is a closed
circuit in which a compressor (21), a condenser (22), an expansion
valve (23), and an evaporator (24) are connected together in this
order by refrigerant piping (20a).
An external fan (25) is disposed near the condenser (22). The
external fan (25) is driven in rotation by an external fan motor
(25a), guides the air in the exterior space of the container (11)
(i.e., outside air) into the external storage space (S1), and sends
it to the condenser (22). In the condenser (22), heat is exchanged
between a refrigerant compressed in the compressor (21) and flowing
through the condenser (22) and the outside air sent from the
external fan (25) to the condenser (22). In this embodiment, the
external fan (25) is comprised of a propeller fan.
Two internal fans (26) are disposed near the evaporator (24). The
internal fans (26) are driven in rotation by internal fan motors
(26a), and draw the air in the container (11) through a suction
opening (18a) and blow the air toward the evaporator (24). In the
evaporator (24), heat is exchanged between a refrigerant having a
pressure dropped by the expansion valve (23) and flowing through
the evaporator (24) and the air in the container sent to the
evaporator (24) by the internal fans (26).
As shown in FIG. 2, each of the internal fans (26) includes a
propeller fan (rotary vane) (27a), a plurality of stator vanes
(27b), and a fan housing (27c). The propeller fan (27a) is coupled
to the internal fan motor (26a), and driven in rotation by the
internal fan motor (26a) about a rotation axis to blow the air in
an axial direction. The plurality of stator vanes (27b) are
disposed on the blowout side of the propeller fan (27a) to rectify
the flow of swirling air blown from the propeller fan (27a). The
fan housing (27c) is comprised of a cylindrical member with the
plurality of stationary vanes (27b) attached to its inner
peripheral surface, and extends to, and surrounds, the outer
periphery of the propeller fan (27a).
As shown in FIG. 1, the compressor (21) and the condenser (22) are
housed in the external storage space (S1). The condenser (22),
located in the middle of the external storage space (S1) in the
vertical direction, divides the external storage space (S1) into a
lower first space (S11) and an upper second space (S12). In the
first space (S11), the compressor (21), an inverter box (29) which
houses a driver circuit for driving the compressor (21) at a
variable velocity, and a gas supply device (30) of the CA system
(60) are disposed. The external fan (25) and an electrical
component box (17) are disposed in the second space (S12). The
first space (S11) is open toward the exterior space of the
container (11). A plate member is arranged to close the second
space (S12) from the exterior space of the container such that only
a blowout port of the external fan (25) is open toward the exterior
space of the container.
As shown in FIG. 2, the evaporator (24) is housed in the secondary
space (S22) of the internal storage space (S2). The two internal
fans (26) are disposed above the evaporator (24) in the internal
storage space (S2) and arranged side by side in the width direction
of the casing (12).
<CA System>
As shown in FIG. 4, the CA system (60) includes a gas supply device
(30), an exhaust portion (46), a sensor unit (50), a controller
(55), and an air inlet unit (80), and controls the oxygen
concentration and carbon dioxide concentration of the air in the
container (11). The term "concentration" to be used in the
following description always indicates a "volumetric
concentration."
[Gas Supply Device]
Configuration of Gas Supply Device
The gas supply device (30) produces nitrogen-enriched air with a
low oxygen concentration to be supplied to the interior of the
container (11). In this embodiment, the gas supply device (30) is
comprised of a vacuum pressure swing adsorption (VPSA)-type device.
Further, the gas supply device (30) is disposed at the lower left
corner of the external storage space (S1), as shown in FIG. 1.
As shown in FIG. 4, the gas supply device (30) includes: an air
circuit (3) connecting together an air pump (31), first and second
directional control valves (32) and (33), and first and second
adsorption columns (34) and (35) each provided with an adsorbent
for adsorbing a nitrogen component in the air; and a unit case (36)
housing these components of the air circuit (3). In this manner,
the gas supply device (30) forms a single unit with these
components housed in the unit case (36), and is configured to be
retrofitted to the container refrigeration apparatus (10).
(Air Pump)
The air pump (31) is provided in the unit case (36), and includes a
first pump mechanism (a pressurizing portion) (31a) and a second
pump mechanism (a depressurizing portion) (31b), each of which
sucks and pressurizes the air and discharges the pressurized air.
The first and second pump mechanisms (31a) and (31b) are connected
to a driving shaft of a motor (31c), and are driven in rotation by
the motor (31c) to suck and pressurize the air, and discharge the
pressurized air.
One end of an outside air passage (41) arranged so as to pass
through the unit case (36) from the interior to exterior of the
unit case (36) is connected to the inlet of the first pump
mechanism (31a). An air-permeable, waterproof membrane filter (76)
is provided at the other end of the outside air passage (41). The
outside air passage (41) is made of a flexible tube. Although not
shown in the drawings, the other end of the outside air passage
(41) where the membrane filter (76) is provided is arranged in the
second space (S12) of the external storage space (S1) above the
condenser (22). Due to this configuration, the first pump mechanism
(31a) sucks and pressurizes the outside air from which moisture has
been removed while flowing from the outside to inside of the unit
case (36) through the membrane filter (76) provided at the other
end of the outside air passage (41). On the other hand, an outlet
of the first pump mechanism (31a) is connected to one end of a
discharge passage (42). The other end (downstream end) of the
discharge passage (42) is divided into two branches, which are
connected to the first directional control valve (32) and the
second directional control valve (33), respectively.
An inlet of the second pump mechanism (31b) is connected to one end
of a suction passage (43). The other end (upstream end) of the
suction passage (43) is divided into two branches, which are
connected to the first and second directional control valves (32)
and (33), respectively. On the other hand, an outlet of the second
pump mechanism (31b) is connected to one end of a supply passage
(44). The other end of the supply passage (44) opens in the
secondary space (S22) on the blowout side of the internal fans (26)
in the internal storage space (S2) of the container (11). The
supply passage (44) is provided with a check valve (65) at the
other end portion thereof. The check valve (65) allows the air to
flow only from one end to the other end of the supply passage (44)
and prevents backflow of the air.
In this embodiment, the discharge passage (42) and the suction
passage (43) are connected together by a bypass passage (47). The
bypass passage (47) is provided with a bypass open/close valve (48)
of which the opening/closing operation is controlled by the
controller (55).
The first and second pump mechanisms (31a) and (31b) of the air
pump (31) are configured as oil-free pumps without lubricant oil.
Two blower fans (49) are disposed on the side of the air pump (31)
to cool the air pump (31) by blowing air to the air pump (31).
(Directional Control Valve)
The first and second directional control valves (32) and (33) are
provided in the air circuit (3) between the air pump (31) and the
first and second absorption columns (34) and (35), and switches the
connection between the air pump (31) and the first and second
absorption columns (34) and (35) among three connection states
(first to third connection states) which will be described later.
This switching operation will be controlled by the controller
(55).
Specifically, the first directional control valve (32) is connected
to the discharge passage (42) connected to the outlet of the first
pump mechanism (31a), the suction passage (43) connected to the
inlet of the second pump mechanism (31b), and one end portion of
the first adsorption column (34) (functioning as an inlet during
pressurization). The first directional control valve (32) switches
between a first state where the first adsorption column (34) is
allowed to communicate with the outlet of the first pump mechanism
(31a) to be blocked from the inlet of the second pump mechanism
(31b) (the state shown in FIG. 4), and a second state where the
first adsorption column (34) is allowed to communicate with the
inlet of the second pump mechanism (31b) to be blocked from the
outlet of the first pump mechanism (31a) (the state shown in FIG.
5).
The second directional control valve (33) is connected to the
discharge passage (42) connected to the outlet of the first pump
mechanism (31a), the suction passage (43) connected to the inlet of
the second pump mechanism (31b), and one end portion of the second
adsorption column (35). The second directional control valve (33)
switches between the first state where the second adsorption column
(35) is allowed to communicate with the inlet of the second pump
mechanism (31b) to be blocked from the outlet of the first pump
mechanism (31a) (the state shown in FIG. 4), and the second state
where the second adsorption column (35) is allowed to communicate
with the outlet of the first pump mechanism (31a) to be blocked
from the inlet of the second pump mechanism (31b) (the state shown
in FIG. 5).
If the first and second directional control valves (32) and (33)
are set to be the first state, the air circuit (3) is switched to a
first connection state where the outlet of the first pump mechanism
(31a) is connected to the first adsorption column (34), and the
inlet of the second pump mechanism (31b) is connected to the second
adsorption column (35) (see FIG. 4). In this state, an adsorption
operation is performed on the first adsorption column (34) to
adsorb a nitrogen component in the outside air onto the adsorbent,
and a desorption operation is performed on the second adsorption
column (35) to desorb the nitrogen component that has been adsorbed
onto the adsorbent.
If the first and second directional control valves (32) and (33)
are set to be the second state, the air circuit (3) is switched to
a second connection state where the outlet of the first pump
mechanism (31a) is connected to the second adsorption column (35),
and the inlet of the second pump mechanism (31b) is connected to
the first adsorption column (34) (see FIG. 5). In this state, the
adsorption operation is performed on the second adsorption column
(35), and the desorption operation is performed on the first
adsorption column (34).
If the first directional control valve (32) is set to be the first
state, and the second directional control valve (33) is set to be
the second state, the air circuit (3) is switched to a third
connection state where the outlet of the first pump mechanism (31a)
is connected to the first adsorption column (34), and the outlet of
the first pump mechanism (31a) is connected to the second
adsorption column (35) (not shown). In this state, both of the
first and second adsorption columns (34) and (35) are connected to
the outlet of the first pump mechanism (31a), which supplies
pressurized outside air to both of the first and second adsorption
columns (34) and (35). In this state, the adsorption operation is
performed on both of the first and second adsorption columns (34)
and (35).
(Adsorption Column)
The first and second adsorption columns (34) and (35) are
configured as cylindrical members filled with an adsorbent. The
adsorbent that fills the first and second adsorption columns (34)
and (35) absorbs a nitrogen component in a state where the
adsorption columns (34, 35) are pressurized, and desorbs the
adsorbed nitrogen component in a state where these adsorption
columns (34, 35) are depressurized.
The adsorbent that fills the first and second adsorption columns
(34) and (35) may be comprised of porous zeolite having pores with
a diameter smaller than the diameter of nitrogen molecules (3.0
angstrom) and larger than the diameter of oxygen molecules (2.8
angstrom), for example. The nitrogen component in the air may be
absorbed by using zeolite having pores of such a diameter as the
adsorbent.
Cations exist in the pores of zeolite, and thus an electric field
has been generated to cause polarity. Therefore, zeolite has the
property of adsorbing polarity molecules such as water molecules.
As a result, the adsorbent made of zeolite and filling the first
and second adsorption columns (34) and (35) adsorbs not only
nitrogen but also moisture (vapor) in the air. The moisture
adsorbed onto the adsorbent is desorbed from the adsorbent together
with the nitrogen component as a result of the desorption
operation. Consequently, nitrogen-enriched air including moisture
is supplied to the interior of the container (11), thus increasing
the humidity in the container (11). Furthermore, the adsorbent is
regenerated, which may extend the adsorbent's life.
In this configuration, if the air pump (31) supplies the
pressurized outside air to the first and second adsorption columns
(34) and (35) to pressurize these columns (34) and (35), the
nitrogen component in the outside air is adsorbed onto the
adsorbent. This produces oxygen-enriched air that has had its
nitrogen concentration lowered and oxygen concentration increased
by including a less nitrogen component than the outside air does.
On the other hand, if the air pump (31) sucks the air from the
first and second adsorption columns (34) and (35) to depressurize
these columns (34) and (35), the nitrogen component that has been
adsorbed onto the adsorbent is desorbed. This produces
nitrogen-enriched air that has had its nitrogen concentration
increased and oxygen concentration lowered by including a more
nitrogen component than the outside air does. In this embodiment,
the nitrogen-enriched air may be 92% nitrogen and 8% oxygen, for
example.
The respective other ends of the first and second adsorption
columns (34) and (35) (functioning as outlets during
pressurization) are connected to one end of an oxygen exhaust
passage (45) through which the oxygen-enriched air that has been
produced in the first and second adsorption columns (34) and (35)
from the pressurized outside air supplied by the first pump
mechanism (31a) is guided toward the outside of the container (11).
The one end of the oxygen exhaust passage (45) is divided into two
branches, which are connected to the other ends of the first and
second adsorption columns (34) and (35), respectively. The other
end of the oxygen exhaust passage (45) opens outside the gas supply
device (30), i.e., outside the container (11). The oxygen exhaust
passage (45) has a portion connected to the other end of the first
adsorption column (34), and a portion connected to the other end of
the second adsorption columns (35). Each of these portions is
provided with a check valve (61) which prevents backflow of the air
from the oxygen exhaust passage (45) toward the first and second
adsorption columns (34) and (35).
A check valve (62) and an orifice (63) are arranged at some
midpoints of the oxygen exhaust passage (45) so as to be
sequentially arranged from one end to the other end of the oxygen
exhaust passage (45). The check valve (62) prevents backflow of the
nitrogen-enriched air from an exhaust connection passage (71),
described later, toward the first and second adsorption columns
(34) and (35). The orifice (63) depressurizes the oxygen-enriched
air which has flowed out of the first and second adsorption columns
(34) and (35) before the oxygen-enriched air is exhausted from the
container.
(Supply-Exhaust Switching Mechanism)
The air circuit (3) is provided with a supply-exhaust switching
mechanism (70) which switches between a gas supply operation,
described later, of supplying the produced nitrogen-enriched air
into the container (11) (see FIGS. 4 and 5), and a gas exhaust
operation of exhausting the produced nitrogen-enriched air to the
outside of the container (11) (not shown). The supply-exhaust
switching mechanism (70) includes an exhaust connection passage
(71), an exhaust open/close valve (72), and a supply open/close
valve (73).
The exhaust connection passage (71) has one end connected to the
supply passage (44), and the other end connected to the oxygen
exhaust passage (45). The other end of the exhaust connection
passage (71) is connected to the oxygen exhaust passage (45) so as
to be located further toward the outside of the container than the
orifice (63).
The exhaust open/close valve (72) is provided to the exhaust
connection passage (71). The exhaust open/close valve (72) is
provided at the midway of the exhaust connection passage (71), and
is comprised of a solenoid valve switching between an open state
where the nitrogen-enriched air that has flowed from the supply
passage (44) is allowed to flow through the exhaust connection
passage (71), and a closed state where the nitrogen-enriched air is
prevented from flowing through the exhaust connection passage (71).
The opening/closing operation of the exhaust open/close valve (72)
is controlled by the controller (55).
The supply open/close valve (73) is provided at the supply passage
(44) so as to be located further toward the other end (toward the
inside of the container) than the junction where the exhaust
connection passage (71) is connected. The supply open/close valve
(73) is provided at the supply passage (44) so as to be located
further toward the inside of the container than the junction where
the exhaust connection passage (71) is connected, and is comprised
of a solenoid valve switching between an open state where the
nitrogen-enriched air is allowed to flow toward the inside of the
container, and a closed state where the nitrogen-enriched air is
prevented from flowing toward the inside of the container. The
opening/closing operation of the supply open/close valve (73) is
controlled by the controller (55).
(Measurement Unit)
The air circuit (3) is provided with a measurement unit (80) used
to perform a supply air measurement operation of measuring the
concentration of the generated nitrogen-enriched air (not shown)
using an oxygen sensor (51) of a sensor unit (50) which is provided
to the interior of the container (11) and which will be described
later. The measurement unit (80) includes a branch pipe (a
measurement passage) (81) and a measurement on-off valve (82), and
is configured to diverge, and guide to the oxygen sensor (51), part
of nitrogen-enriched air passing through the supply passage
(44).
Specifically, the branch pipe (81) has one end connected to the
supply passage (44), and the other end coupled to an oxygen sensor
box (51a), described later, of the oxygen sensor (51). In this
embodiment, the branch pipe (81) is branched from the supply
passage (44) in the unit case (36) and extends from the interior to
exterior of the unit case (36).
The measurement on-off valve (82) is provided to the branch pipe
(81) in the unit case (36). The measurement on-off valve (82) is
comprised of a solenoid valve switching between an open state where
the flow of nitrogen-enriched air in the branch pipe (81) is
allowed, and a closed state where the flow of the nitrogen-enriched
air in the branch pipe (81) is blocked. The opening/closing
operation of the measurement on-off valve (82) is controlled by the
controller (55). As will be described in detail later, the
measurement on-off valve (82) is open only when a supply air
measurement operation to be described later is performed, and is
closed in the other modes.
[Exhaust Portion]
Configuration of Exhaust Portion
As shown in FIG. 2, the exhaust portion (46) includes an exhaust
passage (46a) connecting the internal storage space (S2) to the
exterior space of the container, an exhaust valve (46b) connected
to the exhaust passage (46a), and a membrane filter (46c) provided
to an inlet end (the end adjacent to the interior of the container)
of the exhaust passage (46a). The exhaust passage (46a) passes
through the casing (12) from the interior to exterior of the casing
(12). The exhaust valve (46b) is provided adjacent to the interior
of the exhaust passage (46a), and is comprised of a solenoid valve
switching between an open state where the air is allowed to flow
through the exhaust passage (46a), and a closed state where the air
is prevented from flowing through the exhaust passage (46a). The
opening/closing operation of the exhaust valve (46b) is controlled
by the controller (55).
Operation of Exhaust Portion
When the internal fan (26) is rotating, an exhaust operation is
performed in which the controller (55) opens the exhaust valve
(46b) to exhaust the air (inside air) in the internal storage space
(S2) communicating with the interior of the container to the
outside.
Specifically, when the internal fan (26) is rotating, the pressure
of the secondary space (S22) on the blowout side becomes higher
than the pressure of the exterior space of the container (i.e., the
atmospheric pressure). Thus, when the exhaust valve (46b) is open,
due to the pressure difference between the ends of the exhaust
passage (46a) (the pressure difference between the external space
of the container and the secondary space (S22)), the air in the
internal storage space (S2) communicating with the interior of the
container (inside air) is exhausted out of the container through
the exhaust passage (46a).
[Sensor Unit]
Configuration of Sensor Unit
As shown in FIG. 2, the sensor unit (50) is provided to the
secondary space (S22) on the blowout side of the internal fans (26)
in the internal storage space (S2). The sensor unit (50) includes
an oxygen sensor (51), a carbon dioxide sensor (52), a fixing
member (53), a membrane filter (54), a connection pipe (56), and an
exhaust pipe (57).
The oxygen sensor (51) has an oxygen sensor box (51a) housing a
galvanic-cell sensor therein. The oxygen sensor (51) measures the
value of a current flowing through an electrolytic solution of the
galvanic cell-type sensor to measure the oxygen concentration of a
gas in the oxygen sensor box (51a). An outer surface of the oxygen
sensor box (51a) is fixed to the fixing member (53). Another outer
surface of the oxygen sensor box (51a) opposite from the outer
surface fixed to the fixing member (53) has an opening, to which
the membrane filter (54), that is air-permeable and waterproof, is
attached. In addition, one end of the connection pipe (56) is
coupled via a connector to one of the side surfaces of the oxygen
sensor box (51a). Further, a branch pipe (81) of a measurement unit
(80) is coupled via a connector (pipe joint) to a lower surface of
the oxygen sensor box (51a).
The carbon dioxide sensor (52) has a carbon dioxide sensor box
(52a). The carbon dioxide sensor (52) is a non-dispersive infrared
sensor which radiates infrared rays to the gas in the carbon
dioxide sensor box (52a) to measure an absorption amount of
infrared rays having a wavelength specific to carbon dioxide,
thereby measuring the carbon dioxide concentration in the gas. The
other end of the connection pipe (56) is coupled via a connector to
one side surface of the carbon dioxide sensor box (52a).
Furthermore, one end of the exhaust pipe (57) is coupled via a
connector to the other side surface of the carbon dioxide sensor
box (52a).
The fixing member (53) is fixed to the casing (12) with the oxygen
sensor (51) and the carbon dioxide sensor (52) attached
thereto.
The connection pipe (56) is, as described above, coupled to the one
side surface of the oxygen sensor box (51a) and the one side
surface of the carbon dioxide sensor box (52a), and allows the
internal space of the oxygen sensor box (51a) to communicate with
the internal space of the carbon dioxide sensor box (52a).
As described above, the exhaust pipe (57) has one end coupled to
the other side surface of the carbon dioxide sensor box (52a), and
the other end open near the suction opening of the internal fans
(26). That is, the exhaust pipe (57) allows the internal space of
the carbon dioxide sensor box (52a) to communicate with the primary
space (S21) of the internal storage space (S2).
Concentration Measurement Operation
The secondary and primary spaces (S22) and (S21) of the internal
storage space (S2) communicate with each other via an air passage
(58) formed by the membrane filter (54), the internal space of the
oxygen sensor box (51a), the connection pipe (56), the internal
space of the carbon dioxide sensor box (52a), and the exhaust pipe
(57). Thus, when the internal fans (26) are rotating, the pressure
of the primary space (S21) becomes lower than the pressure of the
secondary space (S22). Due to this pressure difference, the air in
the container flows from the secondary space (S22) to the primary
space (S21) in the air passage (58) to which the oxygen sensor (51)
and the carbon dioxide sensor (52) are connected. As can be seen,
the air sequentially flows from the interior of the container to
the oxygen sensor (51) and the carbon dioxide sensor (52), and then
the oxygen concentration of the air is measured by the oxygen
sensor (51), and the carbon dioxide concentration of the air is
measured by the carbon dioxide sensor (52).
[Controller]
The controller (55) is configured to perform a concentration
control operation for controlling the oxygen concentration and
carbon dioxide concentration of the air in the container (11) to
desired concentrations, respectively. Specifically, the controller
(55) controls the operation of the gas supply device (30) and the
exhaust portion (46) based on measurement results obtained by the
oxygen sensor (51) and the carbon dioxide sensor (52) so that the
composition of the air (the oxygen concentration and carbon dioxide
concentration of the air) in the container (11) are controlled to a
desired target composition (e.g., 3% oxygen and 5% carbon
dioxide).
[Air Inlet Unit]
As shown in FIGS. 1 and 6, the gas supply device (30) is disposed
at the lower left corner of the external storage space (S1) (at the
lower left end of the condenser (22)), whereas the air inlet unit
(75) is disposed at the left of the electrical component box (17)
when the external storage space (S1) is viewed from the front. The
air pump (31) in the unit case (36) is connected to one end of an
air tube (85) constituting the outside air passage (41) sucking
air. The air inlet unit (75) is connected to the other end of the
air tube (85).
FIGS. 7-12 are views illustrating the appearance of the air inlet
unit (75), when viewed from various directions. The air inlet unit
(75) includes an attachment plate (77), an air box (78), and a
filter cover (79). The attachment plate (77) fixes a plurality of
membrane filters (76) to the casing (12) of the container
refrigeration apparatus (10). The air box (78) is fixed to the
upper end portion of the attachment plate (77), and the plurality
of membrane filters (76) are attached to the air box (78). The
filter cover (79) covers the membrane filters (76) from above. The
other end of the air tube (85) is attached to a joint (85a)
provided to the lower surface of the air box (78).
In the attachment plate (77), a recess (77a) is formed in a portion
slightly below the vertically middle portion of the right edge of
the attachment plate (77). This recess (77a) is a recess for
housing a handle (17a) opening/closing the door of the electrical
component box (17). The air box (78) is attached to a portion of
the rear surface of the attachment plate (77) above the recess
(77a).
The air-permeable, waterproof membrane filter (76) is attached to
the top surface, the rear surface, and the left side surface of the
air box (78) when the attachment plate (77) is viewed from the
front. The membrane filter (76) includes a membrane filter body in
which a male screw is formed, and a nut (a female screw) into which
the male screw is screwed (not shown). The membrane filter (76) is
fastened to the top surface, the rear surface, and the left side
surface of the plates of the air box (78) by the male screw and the
female screw. The air box (78) is fixed to the attachment plate
(77) by fastening a nut (78b) to a screw (78a) provided to the air
box (78).
Although the membrane filter (76) itself is waterproof, the filter
cover (79) is provided to prevent water permeation from its
vicinity. The filter cover (79) is a bent member which is c-shaped
when viewed from the side surface. The rear surface of the filter
cover (79) is provided with a hole (79a) into which the membrane
filter at the rear surface of the air box is inserted. This filter
cover (79) is attached to the attachment plate (77) by a screw.
As can be seen, in this embodiment, the air which has passed
through the membrane filter (76) disposed above the condenser (22)
is supplied to the air pump of the gas supply device (30).
Operation
<Operation of Refrigerant Circuit>
In this embodiment, a unit controller (100) shown in FIG. 3
performs a cooling operation for cooling the air in the container
(11).
During the cooling operation, the unit controller (100) controls
the operation of the compressor (21), the expansion valve (23), the
external fan (25), and the internal fans (26) such that the
temperature of the air in the container reaches a desired target
temperature based on measurement results provided by a temperature
sensor (not shown). In this case, the refrigerant circuit (20)
allows the refrigerant to circulate to perform a vapor compression
refrigeration cycle. Then, the air in the container (11) guided to
the internal storage space (S2) by the internal fans (26) is cooled
when passing through the evaporator (24) by the refrigerant flowing
through the evaporator (24). The air in the container cooled by the
evaporator (24) passes through the underfloor path (19a), and is
blown again into the container (11) via the blowout opening (18b).
Thus, the air in the container (11) is cooled.
<Basic Operation of Gas Supply Device>
In the gas supply device (30), a first operation in which the first
adsorption column (34) is pressurized and the second adsorption
column (35) is depressurized (see
FIG. 4), and a second operation in which the first adsorption
column (34) is depressurized and the second adsorption column (35)
is pressurized (see FIG. 5) are alternately repeated every
predetermined time (e.g., 14.5 seconds) to produce the
nitrogen-enriched air and the oxygen-enriched air. In this
embodiment, a pressure equalization operation (not shown) in which
the first and second adsorption columns (34) and (35) are both
pressurized for a predetermined time (e.g., 1.5 seconds) during the
intervals between the first and second operations. The controller
(55) operates the first and second directional control valves (32)
and (33) to perform switching among the operations.
<<First Operation>>
During the first operation, the controller (55) switches the first
and second directional control valves (32) and (33) to the first
state shown in FIG. 4. Thus, the air circuit (3) is set to the
first connection state in which the first adsorption column (34)
communicates with the outlet of the first pump mechanism (31a) and
is blocked from the inlet of the second pump mechanism (31b), and
simultaneously, the second adsorption column (35) communicates with
the inlet of the second pump mechanism (31b) and is blocked from
the outlet of the first pump mechanism (31a).
The first pump mechanism (31a) supplies the pressurized outside air
to the first adsorption column (34). A nitrogen component contained
in the air which has flowed into the first adsorption column (34)
is adsorbed on the adsorbent of the first adsorption column (34).
Thus, during the first operation, the first pump mechanism (31a)
supplies the pressurized outside air to the first adsorption column
(34), in which the adsorbent adsorbs nitrogen component in the
outside air, thereby producing oxygen-enriched air having a lower
nitrogen concentration and a higher oxygen concentration than the
outside air. The oxygen-enriched air flows from the first
adsorption column (34) to the oxygen exhaust passage (45).
On the other hand, the second pump mechanism (31b) sucks the air
from the second adsorption column (35). Simultaneously, the second
pump mechanism (31b) also sucks the nitrogen component adsorbed
onto the adsorbent in the second adsorption column (35) together
with the air, thereby allowing the adsorbent to desorb the nitrogen
component. Thus, during the first operation, the second pump
mechanism (31b) sucks the air out of the second adsorption column
(35) to allow the adsorbent to desorb the nitrogen component
adsorbed thereon. This produces nitrogen-enriched air containing
the nitrogen component desorbed from the adsorbent, and having a
higher nitrogen concentration and a lower oxygen concentration than
the outside air. The nitrogen-enriched air is sucked into the
second pump mechanism (31b), pressurized, and then, discharged
toward the supply passage (44).
<<Second Operation>>
During the second operation, the controller (55) switches the first
and second directional control valves (32) and (33) to the second
state shown in FIG. 5. Thus, the air circuit (3) is set to the
second connection state in which the first adsorption column (34)
communicates with the inlet of the second pump mechanism (31b) and
is blocked from the outlet of the first pump mechanism (31a), and
simultaneously, the second adsorption column (35) communicates with
the outlet of the first pump mechanism (31a) and is blocked from
the inlet of the second pump mechanism (31b).
The first pump mechanism (31a) supplies the pressurized outside air
to the second adsorption column (35). A nitrogen component
contained in the air which has flowed into the second adsorption
column (35) is adsorbed on the adsorbent of the second adsorption
column (35). Thus, during the second operation, the first pump
mechanism (31a) supplies the pressurized outside air to the second
adsorption column (35), in which the adsorbent adsorbs the nitrogen
component in the outside air, thereby producing oxygen-enriched air
having a lower nitrogen concentration and a higher oxygen
concentration than the outside air. The oxygen-enriched air flows
from the second adsorption column (35) to the oxygen exhaust
passage (45).
On the other hand, the second pump mechanism (31b) sucks the air
from the first adsorption column (34). Simultaneously, the second
pump mechanism (31b) also sucks the nitrogen component adsorbed
onto the adsorbent in the first adsorption column (34) together
with the air, thereby allowing the adsorbent to desorb the nitrogen
component. Thus, during the second operation, the second pump
mechanism (31b) sucks the air out of the first adsorption column
(34) to allow the adsorbent to desorb the nitrogen component
adsorbed thereon. This produces nitrogen-enriched air containing
the nitrogen component desorbed from the adsorbent, and having a
higher nitrogen concentration and a lower oxygen concentration than
the outside air. The nitrogen-enriched air is sucked into the
second pump mechanism (31b), pressurized, and then, discharged
toward the supply passage (44).
As mentioned above, in the first operation, the first adsorption
column (34) is pressurized by the first pump mechanism (31a),
thereby performing the adsorption operation, whereas the second
adsorption column (35) is depressurized by the second pump
mechanism (31b), thereby performing the desorption operation. On
the other hand, in the second operation, the second adsorption
column (35) is pressurized by the first pump mechanism (31a),
thereby performing the adsorption operation, whereas the first
adsorption column (34) is depressurized by the second pump
mechanism (31b), thereby performing the desorption operation. Thus,
if the first operation is switched to the second operation or the
second operation is switched to the first operation without the
pressure equalization operation performed during the interval
between the first and second operations, the pressure in the
adsorption column where the desorption operation has been performed
before the switching is remarkably low immediately after the
switching. Thus, it takes time until the pressure in this
adsorption column increases, and the adsorption operation does not
start soon.
Thus, in this embodiment, the air circuit (3) is switched to the
third connection state when the first operation is switched to the
second operation and when the second operation is switched to the
first operation, so that the first and second adsorption columns
(34) and (35) communicate with each other via the first and second
directional control valves (32) and (33). Due to this
configuration, the inner pressures of the first and second
adsorption columns (34) and (35) are immediately equalized (i.e.,
become intermediate pressures between the respective inner
pressures). The pressure equalization operation immediately
increases the pressure in the adsorption column which has been
depressurized by the second pump mechanism (31b) and which has
performed the desorption operation before the switching. Thus, the
adsorption operation is immediately performed after the connection
with the first pump mechanism (31a).
In this manner, the gas supply device (30) alternately repeats the
first and second operations, with the pressure equalization
operation performed during the intervals, thereby producing the
nitrogen-enriched air and the oxygen-enriched air in the air
circuit (3).
Advantages of Embodiment
According to this embodiment, the air inlet unit (75) mounting the
membrane filter (76) thereon is disposed above the unit case (36)
of the inside air control system (60). Thus, the air inlet unit
(75) is less likely to be splashed with sea water even in the
marine atmosphere. This hardly allows water to permeate from the
air inlet unit (75) into the unit case (36) of the inside air
control system (60). Therefore, this can reduce malfunctions of
electrical components and corrosion on metallic components due to
moisture permeation into the unit case (36).
In particular, the air inlet unit (70) is disposed in the space
above the condenser (22). Thus, the air inlet unit (75) is much
less likely to be splashed with sea water. The space above the
condenser (22) is the blowout side space to which the air that has
passed through the condenser (22) is blown, and is the space to
which hot air is blown. Thus, even if the air inlet unit (75) is
splashed with sea water, the water is likely to be evaporated. As a
result, water further hardly permeates into the unit case (36) of
the inside air control system (60), thereby making it possible to
more reliably reduce malfunctions of electrical components in the
unit case (36) and corrosion on metallic components in the unit
case (36).
The filter cover (79) is provided to cover the membrane filter
(76). Thus, the membrane filter (76) is also less likely to be
splashed with sea water. This makes it possible to more reliably
reduce malfunctions of electrical components in the unit case (36)
and corrosion on metallic components in the unit case (36). Also,
the air box (78) of the air inlet unit (75) can be disposed by
effectively utilizing the space disposed above the condenser (22)
and on the side of the electrical component box (17).
Other Embodiments
The above embodiments may also be configured as follows.
For example, in the above embodiment, the air inlet unit (75)
provided with the membrane filters (76) is disposed adjacent to the
electrical component box (17). Alternatively, as long as the air
inlet unit (75) is disposed above the unit case (36) of the inside
air control system (60), the position of the air inlet unit (75)
may be changed according to the specific configuration of the
container refrigeration apparatus (10).
Also, in the above embodiment, the air inlet unit (75) provided
with the membrane filters (76) is comprised of the attachment plate
(77), the air box (78), and the filter cover (79). Alternatively,
the configuration of the air inlet unit (75) may also be changed
according to the specific configuration of the container
refrigeration apparatus (10) and arrangement of components of the
container refrigeration apparatus (10).
Note that the foregoing description of the embodiment is a merely
beneficial example in nature, and is not intended to limit the
scope, application, or uses of the present disclosure.
INDUSTRIAL APPLICABILITY
As can be seen from the foregoing description, the present
invention is useful as a container refrigeration apparatus
including an inside air control system which supplies a mixed gas
such as a nitrogen mixed gas into a container.
DESCRIPTION OF REFERENCE CHARACTERS
10 Container Refrigeration Apparatus 11 Container 17 Electrical
Component Box 22 Condenser 31 Air Pump 36 Unit Case 60 Inside Air
Control System (CA system) 75 Air Inlet Unit 76 Membrane Filter 78
Air Box 79 Filter Cover 85 Air Tube S1 External Storage Space
* * * * *